AN EXAMINATION OF THE ALTERNATIVE METHODS USED BY THE INVESTMENT CASTING INDUSTRY TO PRODUCE SACRIFICIAL PATTERNS: HAVE ALL OF THE AVAILABLE OPTIONS BEEN CONSIDERED?

摘要

The investment casting (IC) process has remained relatively unchanged throughout recorded history [1]. Indeed, there have been refinements to the individual processes required to produce castings; pattern making, the ceramic materials used to create the molds, foundry equipment, and post-cast processing of the castings. All have undergone numerous improvements. Yet, with the innovations that IC foundries have enjoyed, the casting process still requires a one-to-one ratio to produce an IC component from a sacrificial master pattern [2]. It is the alternative technologies used to produce the sacrificial master pattern that are the focus of this paper.New product development and introduction (NPDI) of an IC component requires the expertise of several engineering disciplines. Communications between the various engineering disciplines are critical to assure that cost effective decisions during product design and process development are made. With that in mind, several of the options available to the engineering teams responsible for NPDI are explored in the subsequent text.Rapid prototype (RP) technologies have played a crucial role during NPDI. The patterns produced using the various forms of RP technologies have allowed the IC industry to be considered by design engineers as a viable manufacturing option for their products.A more recent development in the United States is rapid tooling (RT). RT is an additive process, using metal to build the individual layers of the cavity block or the cavity insert. The finished component can then be used as a wax pattern cavity.Engineering teams should also consider a combination of RT and traditional wax pattern tooling. The complex pattern cavities are produced using RT while the more simple components are produced using traditional tooling.For IC foundries to be competitive all available pattern making options must be considered. Multi-disciplinedengineering teams will play an important role choosing the technologies discussed. With careful consideration, the engineering teams responsible for NPDI can ensure the future of the IC industry.